My thesis advisor is absent in my final stage of completing my Ph.D. programme

I am a mathematics Ph.D. student who are in my final stage of completing my Ph.D. programme. My advisor is visiting an institute for a few months. The institute that he is visiting is in another country; because of the visa requirements and many other practical reasons, I cannot go there with him.

Now my progress is, I have all the main results ready (most of them have been written down) and I need to finish writing my thesis in about three weeks. My advisor has guided my through all the mathematical difficulties; now he left me behind to write the thesis all by my own. Furthermore, he has clearly indicated that he will NOT help me with the writing process.

Now I need to figure out many things all by myself, from LaTeX to the organization, from the usage of languages to drawing pictures, etc. Also I need to verify the correctness and validity of all the results; he mentioned that he will not carefully read my draft. And I do not have much time to finish everything. I am feeling somewhat stressed and overwhelming.

Anyone has some suggestions for me?